CPDLC messages are used for communication between controller and pilot. Traditionally, all received and sent messages are displayed in a list box format. The pilot normally opens up the list box and opens an individual message to read. The pilot must navigate between review and new menus to read the messages. There are several different message types, such as reports, conditional clearances, and loadable messages. In the case of reports, a report is formed and sent when a particular scenario or set of conditions is met.